Techniques and methods developed for Conversational Question Answering over Knowledge Bases (C-KBQA) are fundamental to the knowledge base search module of a CIR system, as shown in Figure REF . Unlike the machine comprehension module (Chapter ), which has to rely on the documents retrieved by the document search module to generate answers, the knowledge base search module can be used as a standalone system, known as a C-KBQA system, which generates the answer to an input query by reasoning over its knowledge base.
Many task-oriented dialog systems are implemented as instances of a C-KBQA system [1]}. These systems consist of many dialog components that have counterparts in a CIR system as in Figure REF , such as contextual query understanding, dialog policy, dialog state tracker, clarifying question generation, and response generation.
